Glossary
Instruction Manual: Professional Decoder
Page A-5
ST.TM.TT1220.1
LED
Light Emitting Diode.
LNB (Low Noise Block
Down-Converter)
The component of a subscriber satellite transmission receiving dish which amplifies the incoming signal and down-
converts it to a suitable frequency to input to the IRD (typically 950 MHz - 1600 MHz).
LO
Local Oscillator.
LSB
Least significant bit.
LVDS
Low Voltage Differential Signal.
Also:
Low Voltage Differential Serial interface.
Macroblock
The four 8 x 8 blocks of luminance data and the two (for 4:2:0 chrominance format), four (for 4:2:2) or eight (for 4:4:4)
corresponding 8 x 8 blocks of chrominance data coming from a 16 x 16 section of the luminance component of the
picture. Macroblock can be used to refer to the sample data and to the coded representation of the sample values
and other data elements.
Mbps
Mega (million) bits per second.
MCC (Multiplex Control
Computer)
A component of the compression system. Using information from the AFS, the MCC sets up the configuration for the
multiplexers under its control. An MCC controls the main and backup multiplexer for each transport stream.
MCPC
Multiple Channels Per Carrier.
MEM
One of the range of Tandberg Television compression system control element products. The MEM holds a model of
the system hardware. Using this model, it controls the individual system elements to configure the output multiplexes
from the incoming elementary streams. The MEM monitors the equipment status and controls any redundancy
switching.
MMDS (Multichannel
Microwave Distribution
System)
A terrestrial microwave direct-to-home broadcast transmission system.
Motion Compensation
The use of motion vectors to improve the efficiency of the prediction of sample values. The prediction uses motion
vectors to provide offsets into the past and/or future reference frames or fields containing previously decoded sample
values that are used to form the prediction error signal.
Motion Estimation
The process of estimating motion vectors in the encoding process.
Motion Vector
A two-dimensional vector used for motion compensation that provides an offset from the co-ordinate position in the
current picture or field to the co-ordinates in a reference frame or field.
MP@ML (Main Profile Main
Level)
A subset of the MPEG-2 standard which supports digital video transmissions from around 2 to 15 Mbit/s over both
satellite and cable channels.
MPEG (Moving Pictures
Experts Group)
The name of the ISO/IEC working group which sets up the international standards for digital television source coding.
MPEG-2
Industry standard for video and audio source coding using compression and multiplexing techniques to minimise
video signal bit-rate in preparation for broadcasting. Also known as ISO/IEC 13818 [1]. Supersedes the MPEG-1
standard. The standard is split into layers and profiles defining bit-rates and picture resolutions.
MSB
Most significant bit.
MSymbol/s
Mega Symbols per second (10
6
Symbols per second)
Multiplex
A number of discrete data streams (typically 8 to 12) from encoders that are compressed together in a single DVB
compliant transport stream for delivery to a modulator.
MUSICAM (Masking pattern
adapted Universal Sub-
band Integrated Coding
And Multiplexing)
An audio bit-rate reduction system relying on sub-band coding and psychoacoustic masking.
Mux (Multiplexer)
Transmission multiplexer: receives EMMs from the ACC, ECMs from the BCC, video/audio data from the encoders,
and the SI stream from the SIC. It then multiplexes them all into a single DVB-compliant transport stream, and
delivers the signal to the uplink after modulation.
The multiplexer also contains the cypher card which scrambles the services according to the control words supplied
by the BCC.
Network
In the context of broadcasting: a collection of MPEG-2 transport stream multiplexes transmitted on a single delivery
system, for example, all digital channels on a specific cable system.
NICAM (Near
Instantaneously
Companded Audio
Multiplex)